F1 | Mercedes engine case: FIA updates rules but W17 remains compliant. The FIA updates rules for engine compression tests ahead of the 2026 F1 season.

There’s a new development in the ongoing Mercedes engine case: the FIA is expected to revise the rules, but the team at Brackley remains confident that they are fully compliant.

This week, Bahrain is not only hosting the official pre-season tests that kick off the 2026 Formula 1 season. Discussions continue about the controversy surrounding the Mercedes engine and what the FIA’s decision will be regarding compression ratio testing. The Federation has made no secret of its intention to clarify the situation before the season opener in Australia, ensuring all teams understand the regulations before the first race.

The FIA’s decision on the Mercedes engine

According to multiple reports on the morning of Day 2, the FIA is expected to update the current regulations. In particular, high-temperature tests could be added to check what may be the variable compression ratio of the different power units. The goal is clear: to finally silence rumors about Mercedes and prevent any potential protests from rival engine manufacturers.

Adding intrigue to the story, AutoSprint revealed a remarkable development. Journalist Fulvio Solms reports that the FIA secretly tested the Silver Arrows’ engine without informing the other manufacturers. Surprisingly, the team at Brackley reportedly passed all checks without any issues. What remains to be seen is whether this will force Mercedes to use a less powerful engine than initially designed, or if the W17 will continue to enjoy its full performance advantage.

For now, Brackley appears confident, and the new rule changes seem aimed at clarifying procedures rather than penalizing the team. The coming days of testing in Bahrain will likely show how these updates affect engine performance, but Mercedes fans can rest assured that the W17 remains fully within the regulations as they prepare for the 2026 season.

Overall, the outcome of this dispute will likely define the opening races of the season. If Mercedes can maintain its rumored power advantage under the new testing protocols, the rest of the field will be facing a steep uphill climb. As the Bahrain test concludes and the focus shifts to Australia, the “PU Gate” saga serves as a reminder that in Formula 1, the most important battles are often fought in the fine print of the rulebook and the secret corners of the FIA inspection bay.